"Ginormous" has been added to the Merriam-Webster's Collegiate Dictionary. Here are some of the other words added this year: Bollywood, crunk, DVR, flex-cuff, RPG, and sudoku. The funny thing is that when you click on the words listed in the announcement, you get the following message: "The word you've entered isn't in the dictionary." (Fixed now.) Link (Thanks, Jennifer Lum!)
UPDATE: As several readers pointed out, it's odd that the definition of "RPG" does not include "role playing game."
UPDATE: BB reader Ethan Ham emailed Merriam-Webster's customer service to ask why they don't include "role playing game" in the "RPG" definition. The company's response is below. If you have any comments or suggestions related to this topic, please send them to Merriam-Webster and not to me. Thanks! From Merriam-Webster's response:
Thanks for your e-mail about "RPG." We are aware of the "role
playing game" expansion, but do not have enough evidence of it in
printed edited prose to yet merit its entry. For a full discussion
of how a word (or abbreviation) is entered into our dictionaries,
please visit www.Merriam-Webster.com/help/faq/words_in.htm.